src: Remove unused 'include <arch/cpu.h>'

Change-Id: Iaa236f07aed52ccb8c4839047894a14a9446a109
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36080
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/southbridge/intel/ibexpeak/lpc.c

@@ -27,7 +27,6 @@
 #include <device/pci_ops.h>
 #include <arch/ioapic.h>
 #include <arch/acpi.h>
-#include <arch/cpu.h>
 #include <elog.h>
 #include <arch/acpigen.h>
 #include <drivers/intel/gma/i915.h>